Blind encryption

Abstract

A method of processing encrypted communications sent by a first party, the method including the steps of: receiving from the first party a message that has a first part, a second part, a third part and a fourth part, wherein the first part includes a first block of information that is encrypted by using a key k1, the second part includes a second block of information that is encrypted by using a key k2, the third part includes a third block of information that is encrypted by using a key R, and the fourth part includes a fourth block of information that is encrypted by using the key R, wherein the third block of information includes k1 and the fourth block of information includes k2; blinding the fourth part; sending the third part and the blinded fourth part to a recryptor; receiving from the recryptor the k1 key re-encrypted by using a first key; and receiving from the recryptor a fifth block of information which is the blinded fourth block of information that has been encrypted by using a second key.

What is claimed is: 
     
       1. An encryption method comprising: receiving from a first party a message that has a first part, wherein the first part includes a first block of information that is encrypted by using a public key R of a recryptor's public key-private key pair;   blinding the first part;   sending the blinded first part to a recryptor; and   receiving from the recryptor a second block of information which is the first block of information blinded and decrypted using the private key of the recryptor's public key-private key pair.   
     
     
       2. The encryption method of claim 1 further comprising unblinding the second block of information. 
     
     
       3. An encryption method comprising: receiving from a first party a blinded message that was also encrypted by using a public key R of a public key-private key pair;   decrypting the blinded message by using the private key of the public key-private key pair; and   sending the decrypted, blinded message back to the first party.